Combustion Flashcards
If only 2 units of oxygen are required for complete combustion of 1 unit of methane, why must 10 units of air be supplied for complete combustion of 1 unit of methane
There are 2 units of oxygen in 10 units of air
An inspirated burner is found on a?
Natural draft appliance
What force makes stack action possible
Buoyancy
A flame with a two part cone is developed by what type of burner
Pre mix burner
What is the maximum equivalent length of a combustion air duct ducting allowed without increasing the size
20 feet
Combustion air sizing is taken from the appliances ———?
Input rating
Define the term combustion
The rapid oxidation of fuel resulting in the production of heat or heat and light
When gas burns properly, the hydrogen combines with the oxygen of the air to produce—————-, the carbon combines with the oxygen to produce————- and the ————— in the air passes through the flame unchanged.
Water vapour
Carbon dioxide
Nitrogen
Define combustion air
The air required to completely burn the fuel
Define primary air
Air required for the initial stages of the combustion process and is mixed with the fuel prior to combustion
Define secondary air
Air required for the intermediate and final stages of the combustion process and is mixed with the fuel prior to combustion
Define excess air
Air supplied for the combustion process in excess of, but not required theoretically
Define combustion products
Constituents resulting by uniting the fuel with oxygen, usually thought of as being gas, primary air or secondary air
Define range of flammability
The percentage of gas present in a gas/ air mixture between the upper and lower limits that will burn
Define incomplete combustion
Combustion that does not convert all the carbon and or hydrogen into water vapour and or carbon dioxide
Define lift off
The gas/air mixture speed exceeds the flame speed resulting in a flame that burns too high above the burner
Define flashback
The gas/air mixture is slower than the flame speed causing the flame to burn inside the burner, possibly at the orifice
What 3 components are required for combustion
Fuel
Heat (ignition)
Oxygen (air)
What product creates concern when incomplete combustion occurs
Carbon monoxide (Co)
What flame color is most likely to indicate poor combustion
Yellow
What flame color usually indicates dust or dirt passing through the flames
Orange
What colour of flame indicates good combustion
Blue
What are the two constituents of the products of combustion that can form due to incomplete combustion of fuel
Aldehydes and carbon monoxide
A compound that consists of only hydrogen and carbon would be a definition of?
Hydrocarbon
